This invention relates to connectors for tubular conduits having telescoping ends which overlap, and more particularly to exhaust system clamps for securing together interfitted exhaust pipes and the like.
All types of vehicles, especially automobiles and trucks, employing an internal combustion engine generally have an exhaust system comprised of a muffler, catalytic convertor, resonator, or combination thereof, for treating the exhaust gas before it is discharged into the atmosphere and/or abating noise. The various components of the exhaust system are generally connected together by one or more conduits or pipes to form a continuous pathway for exhaust gases from the exhaust manifold, through the components of the exhaust system and out of the tailpipe.
The major components of the exhaust system such as the muffler, catalytic convertor and resonator are generally provided with an inlet tube and an outlet tube which are welded or otherwise secured to the component in a substantially leak proof, gas-type manner. The inner diameter of the tubes from the components, such as an outlet tube from the muffler, have an inner diameter which is about equal to the outer diameter of the connecting pipes so that an end of a connecting pipe can be slipped over the end of the tube from the muffler or other component to form a slip-joint or lap-joint. In order to secure the overlapped pipes together, a connector is used to apply a substantially uniform, radially inwardly directed compressive force about the circumference of the lap-joint. It is generally desirable to have the connector apply sufficient force uniformly about a circumference of the lap-joint to inwardly deform the overlapping tubes to form a substantially continuous bead or protuberance along the inner surfaces of the pipes.
A variety of clamps have been developed to apply the desired radially inwardly directed compressive forces about the circumference of a lap-joint to secure telescoped pipes together. One of the most common pipe connectors used for connecting exhaust pipes is a guillotine or saddle type clamp comprised of a U-bolt and a saddle or yoke having a web with a semicircular cutout portion. The U-bolt has a substantially semicircular curved section with a radius of curvature which is substantially equal to the outside radius of the outer of the two overlapping tubes or pipes which are to be joined together, and the semicircular cutout of the yoke has a similar radius. The U-bolt also has two parallel legs which extend from the ends of the semicircular curved portion thereof. The yoke is generally prepared from a sheet of steel which is cut, stamped and rolled to provide the web with the semicircular cutout. The yoke also includes apertures or tubular portions for receiving the ends of the U-bolt. The saddle and U-bolt are placed over a lap-joint between telescoped ends of exhaust pipes, with the edge of the semicircular cutout and the inner perimeter of the semicircular portion of the U-bolt facing the outer circumference of the lap joint, and with the ends of the straight leg portions of the U-bolt projecting through the apertures or tubular portions of the yoke. The yoke and U-bolt are then forced toward each other by a pair of nuts threaded on to the ends of the U-bolt legs to apply substantially uniform radially compressive forces continuously around a circumference of the lap-joint.
A disadvantage with conventional saddle or guillotine type clamps is that they include four separate components, including a yoke, a bolt and two nuts, which must be handled and brought together during mounting of the clamp to overlapped ends of exhaust pipes. As a result considerable time and effort must be expended to mount such clamps to connect exhaust pipes. Specifically, mounting requires first properly aligning the U-bolt with the yoke, then inserting the ends of the U-bolt through tubular portions or apertures in the yoke, and finally threading and tightening the two nuts onto the threaded ends of the U-bolt.
Various loop-type circumferential connectors or exhaust clamps comprised of a looped band or bolt having an eyelet or internally threaded extension at one end and an externally threaded extension at the other end have been proposed. Such clamps are disclosed for example in U.S. Pat. Nos. 3,774,270; 4,365,392 and 4,558,891. In each case, the externally threaded extension at one end of the loop is inserted through an eyelet or a tubular extension at the other end, and the nut is threaded and tightened onto the externally threaded extension to cause the loop to contract around the telescoped pipes of an exhaust system.
These loop-type connectors have the advantage of being comprised of only two parts, including a looped band and a nut, whereby mounting of the connector to telescoped pipes is considerably simplified. Specifically, installation typically involves placing the looped band over one end of the tube pipes which are to be connected, inserting the end of the smaller diameter tube into the end of the larger diameter tube to form a slip-joint, repositioning the looped band over a central circumference of the slip-joint if necessary, and threading and tightening a nut onto the externally threaded extension. As an alternative, it may be possible in some cases to connect the ends of the exhaust pipes together first and then slip the loop-type clamp over the unconnected ends one of one of the pipes, slide the clamp along the length of the pipe and over the lap-joint. However, this latter mounting procedure is generally difficult and time consuming at best, and often impractical or impossible.
A resulting disadvantage with the loop-type clamps is that, in general, it is exceedingly difficult or impossible to remove these clamps without first completely separating the pipes on which the clamp is located. Likewise, it must be kept in mind that mounting of the clamp will generally require slipping the clamp over one of the pipe ends which are to be connected together before the tubes are connected. Accordingly, any adjustments which might be required during installation or repair of an exhaust system can be difficult and cumbersome when such loop-type clamps are used.